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Naval Postgraduate Dental School
Clinical Update National Naval Dental Center
8901 Wisconsin Ave
Bethesda, Maryland 20889-5602
Vol. 26, No. 5 May 2004
Porcelain veneers – part II: preparation and delivery
Lieutenant Yaohsien Peng, DC, USNR, Captain Blaine Cook, DC, USN, and
Captain Dean Beatty, DC, USN
Introduction
Porcelain Veneers Part I, July 2003, reviewed the evaluation and In preparing diastema closure, the interproximal preparation is
treatment planning phases of porcelain veneer restorations. Part II extended through the contact toward the lingual. The greater
will address clinical techniques used in tooth preparation, delivery, the space to be closed, the farther the preparation must be
and the post-operative phases of treatment. carried to the lingual. It is also important to extend the
interproximal preparation subgingivally to recontour the
Traditional preparation design papilla. This type of preparation must be provisionalized to
Traditional veneer preparation is a conservative reduction of tooth reduce sensitivity and prevent migration (1).
structure consisting of 0.5mm facial reduction with interproximal
finish lines facial to the contact area. Because all prepared surfaces Material options
are generally in enamel and contacts are left undisturbed, the need Feldspathic porcelain. Traditionally, ceramic veneers are
for temporization is minimized and the potential for pulpal fabricated by layering feldspathic porcelain onto a refractory
involvement is significantly reduced. Supragingival veneer margins die or platinum foil (3).
avoid the risk of irritation to periodontal tissues (1). Densely sintered high-purity magnesium oxide base coping, e.g.
In-Ceram Spinell. The core is more translucent than the
Preparation Procedure: traditional In-Ceram but does not posses the same flexure
1. Retract gingival tissue if necessary. strength. It can be veneered with feldspathic porcelain but is
2. Make a series of facial depth cuts by either using round carbide not necessary.
burs, or BrasselerTM or NixonTM depth cutters. Reduction of 0.5 Heat-pressed ceramic material, e.g. IPS Empress. Leucite-
mm is usually adequate and should follow the anatomic reinforced feldspathic porcelain has improved flexural strength,
contours of the teeth. fracture resistance, and excellent marginal adaptation. It can
3. Place a “long chamfer” margin with an obtuse cavosurface also be veneered with feldspathic porcelain.
angle, which exposes the enamel prism ends at the margin for
better etching. The margin should closely follow the gingival Veneer delivery procedures
crest. Preliminary inspection
4. Place the preparation margin labial to the proximal contact area Examine veneers under magnification.
to preserve it in enamel. Check fit of veneers on dies by first trying veneers one-at-a-
5. Do not reduce the incisal edge if possible; this helps support the time and then all together.
porcelain and makes chipping less likely. If the incisal length is Clean the restorations thoroughly in water with ultrasonic
to be increased, the tooth should be reduced to allow for a agitation.
minimum of 1.5mm of porcelain. Tooth Preparation
6. Avoid undercuts and visualize the path of insertion because an Thoroughly clean the preparations, making sure all provisional
undercut will prevent placement of the veneer. luting agents are removed.
7. Connect depth cuts and margins. To prevent areas of stress Try-in restorations with water, first one-at-a-time and then all
concentration in the porcelain, ensure the tooth preparation is together. Verify fit, shade, and insertion sequence.
free of sharp angles. All prepared surfaces should be rounded Color Check and Characterization
and smoothly flowing.
Place one laminate in position with water or glycerine and then
compare it to the shade tab selected. If the laminate appears
Alternate preparation designs
dark, then a lighter colored resin cement should be selected.
Ultraconservative preparation design is more conservative than Utilize color-keyed try-in pastes to evaluate and select the
the traditional veneer preparation, which can result in dentin appropriate shade (4).
exposure in the cervical areas. This preparation design
Veneers can also be characterized externally using a special
advocates cervical reduction of 0.3mm and midfacial reduction
laminate low-fusing color system, which fuses at approximately
of 0.3mm to 0.5mm, which takes into account the mean thick-
1,400F. The laminate can also be supported with an instant
ness of enamel (2).
investment, which when set facilitates coloring and glazing with
Extending traditional veneer preparation is appropriate for
any conventional system (4).
situations requiring hidden margins, or increased retention. In
Cementation
this design, proximal margins are extended into or through the
Use rubber dam isolation or displacement cord, cotton rolls,
contacts and the gingival margins are placed slightly
and cheek retractors.
subgingival. It is indicated for malaligned teeth, discoloration,
Clean the teeth with pumice. Wash and dry.
black space closure, veneers adjacent to crowns, replacing
restoration or wrapping an existing restoration, and diastema
closure (1).
35
Check with the dental laboratory to see if the fabricated veneers There is also an increase in papillary bleeding on probing in
were etched. If not, etch the internal surface of the veneer with 25% of restored teeth with subgingival restoration margins (7).
hydrofluoric acid for 5 minutes. Rinse and dry. Subgingivally placed margins of dental restorations are
Silane is painted onto the etched porcelain to enhance the associated with pathologic alteration of the adjacent gingiva;
adhesive properties of the resin. Allow to dry for one minute the greater the marginal inaccuracy of the restoration, the
and gently air-dry the veneer surface (4, 5). greater the permanent damage to the periodontal tissue (7).
Place a Mylar matrix strip, dead soft metal matrix, or plumber’s
teflon tape interproximally to protect adjacent teeth. Maintenance
Etch the enamel with 37% phosphoric acid for 30 seconds. Resin polymerization takes at least 72 hours to complete.
Rinse thoroughly and dry. During this early phase, hard and extremely hot or cold food,
Following the manufacturer’s instructions for cementing alcohol and medicated mouthwashes should be avoided. (4)
veneers, apply bonding agent to etched enamel and etched, Patients will have a period of adjustment for the first two weeks
silanated veneer surface but do not light cure. as they get used to the "new" teeth that changed in size and
Apply light cure composite resin luting agent to the restoration. shape.
Be careful to avoid trapping air. Patients should be instructed to use a soft toothbrush with
Position the restoration gently, seating veneer from incisal to rounded bristles, and to floss daily.
gingival. Remove excess luting agent with an instrument. Patients should also avoid biting on hard objects/food with
Hold the restoration in place while light-curing the resin. Do restored teeth.
not press on the center of veneers; they may flex and break. Routine cleanings are recommended at least every four months
Remove excess cement before full cure being careful not to pull with a hygienist. Ultrasonic scalers and air abrasion systems
cement out from veneer margin leaving a defect. should be avoided.
Light cure for 40 seconds from several directions for 2-3 A hard night guard is useful to decrease the potential for
minutes cumulative cure time per veneer. fracture of the laminate and excessive wear of the opposing
Finishing arch. A soft acrylic mouth guard should be used for any form
Remove resin flash with a scalpel or sharp curette. of contact sports.
It is important to realize that the unsupported porcelain veneer
should never be contoured until bonding is completed. References
Finish accessible margins and occlusion with fine diamonds, 1. Rouse JS. Full veneer versus traditional veneer preparation: a
using water spray. Use finishing strips for the interproximal discussion of interproximal extension. J Prosthet Dent. 1997 Dec;
margins. 78(6): 545-9.
Polish adjusted areas with an intra-oral porcelain polishing 2. Rouse J, McGowan S. Restoration of the anterior maxilla with
system (rubber wheels or points, diamond polishing paste, etc.) ultraconservative veneers: clinical and laboratory considerations.
Caution: for pressable systems, e.g. Empress, the color is on Pract Periodontics Aesthet Dent. 1999 Apr;11(3):333-9.
the surface and can be polished away. 3. Zhang F, Heydecke G, Razzoog ME. Double-layer porcelain
veneers: effect of layering on resulting veneer color. J Prosthet
Seating sequence in multi-unit case Dent. 2000 Oct;84(4):425-31.
Start with the two central incisors. It is essential that the veneers of 4. Garber DA, Goldstein RE, Feinman RA. Porcelain Laminate
the central incisors be positioned correctly. The two lateral incisors Veneers. Quintessence Publishing Co. 1988: 90-98.
are then seated, one at a time, to accommodate any discrepancies in 5. Kamada K, Yoshida K, Atsuta M. Effect of ceramic surface
overall fit (4). There are numerous opinions about the cementation treatments on the bond of four resin luting agents to a ceramic
sequence of the remaining veneers. Minor adjustments made on material. J Prosthet Dent. 1998 May;79(5):508-13.
posterior teeth can be accomplished without jeopardizing esthetics. 6. Dumfahrt H, Schaffer H. Porcelain laminate veneers. A
retrospective evaluation after 1 to 10 years of service: Part II-
Factors influencing veneer failure Clinical results. Int J Prosthodont. 2000 Jan-Feb;13(1):9-18.
Adhesion of the veneer seems to be the most important factor to 7. Christgau M, Friedl KH, Schmalz G, Resch U. Marginal
reduce the compressive and tensile stresses in the veneer. adaptation of heat-pressed glass-ceramic veneers to dentin in vitro.
Contamination during bonding significantly decreases the bond Oper Dent. 1999 May-Jun;24(3):137-46.
strength of the porcelain veneers.
LT Peng is a third year resident in the Prosthodontics Department.
Higher porcelain veneer failure rates have been observed when
Captain Cook is the Chairman of the Operative Dentistry
the gingival margin is located on dentin. Today's dentin
Department and Captain Beatty is a faculty member in the
bonding agents are improved over previous generations but no
Prosthodontics Department at the Naval Postgraduate Dental
long-term data exist indicating the expected longevity of
School.
bonded dentin margins (6). Ideally all veneer margins should
be on enamel. When cervical margins must be on dentin,
The opinions and assertions contained in this article are the private
utilize highly filled, viscous resin cements and dentin bonding
ones of the authors and are not to be construed as official or
agents of the latest generation to achieve greatest longevity (6).
reflecting the views of the Department of the Navy.
Patients who smoke increase their risk of veneer failure due to
staining at the veneer margins (6).
Note: The mention of any brand names in this Clinical Update does
There is an increase in gingival recession in 31% of the
not imply recommendation or endorsement by the Department of the
patients, which ranged from 0.1 to 0.5mm. 88% of the
Navy, Department of Defense, or the U.S. Government.
recession is localized in teeth where the margin is subgingival.
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